1. Field of the Invention
The present invention relates to a dialyzing apparatus which can quickly remove water from blood of a patient who may have arteriosclerosis, without causing an abrupt blood-pressure decrease in the patient.
2. Related Art Statement
There is known a dialyzing apparatus which artificially removes, by utilizing osmotic-pressure difference or ultrafiltration, urea, uric acid, or creatinine, together with water, from blood of a patient. When the dialyzing apparatus is used, a patient whose blood circulates through the apparatus, and a doctor who attends to the patient cannot move away from the apparatus, for at least several hours. Therefore, it is desired to increase the water-remove rate and thereby quickly finish the dialysis operation. However, if the water-remove rate is excessively high, the patient may fall in a shock. To avoid this, an appropriate water-remove rate is manually set to obtain a target water amount to be removed for a dialysis duration of from 4 to 5 hours, in view of a standard body weight and a measured body weight of the patient and a water-remove capacity. The water-remove rate is defined as an amount of fluid that permeates per unit time from the blood of the patient into the dialyzing fluid present in the dialyzer through the dialysis membrane, and the amount of fluid can be changed by changing a pressure difference over the dialysis membrane, e.g., a rotation speed of a negative-pressure pump which produces the pressure difference over the dialysis membrane.
Meanwhile, softness of arteries of a patient who has arteriosclerosis is low and accordingly, during a dialysis operation, blood pressure of the patient may abruptly decrease and fall in a shock. However, since it has been a conventional practice to set a water-remove rate irrespective of whether a patient has arteriosclerosis, there have been a considerably large number of cases where a patient who has arteriosclerosis fall in a shock during a dialysis operation.